The present invention relates to the field of telemetry involving the electronic extraction of information from a plurality of remotely located traffic monitoring stations, transmission of the information using two-way paging technology, and providing access to the information to multiple users via the Internet
State departments of transportation currently deploy remote roadside devices to collect traffic information for monitoring highway performance characteristics. Some roadside devices, such as actuated traffic signal controllers, are deployed to monitor, control and manage either an individual traffic signal, or a group of traffic signals, at intersections. The traffic information collected by these devices may include such data as traffic volumes (number of vehicles passing a particular section of the highway during a certain period), or speed, to name only a few. Information from the traffic monitoring devices is extracted either manually, as disclosed in U.S. Pat. No. 4,916,621 to Bean et al., or remotely downloaded to a central computer using traditional data communication methods. The collected information is useful to a number of groups within the transportation department as well as private traveler-information service providers (TISP). The TISPs utilize this information to inform individuals of the prevailing traffic conditions of a given roadway.
Traditional data communication methods between a roadside traffic monitoring device and a central computer include both wireline and wireless. These methods have been exhaustively disclosed in prior patents (see, for example, U.S. Pat. No. 5,317,311 to Martell et al., U.S. Pat. No. 5,528,234 to Mani et. al., and U.S. Pat. No. 5,889,477 to Fasternath.). Wireline techniques commonly employ a modem with dial-up or leased-line telephone lines, or dedicated underground or overhead cables. Wireless techniques commonly include modems based upon narrowband-radio, cellular, microwave or spread-spectrum frequencies. Each of the above wireline and wireless communication methods has proved to be either difficult to install or cost-ineffective for a region-wide implementation.
U.S. Pat. No. 5,835,026 to Wicks et al. discloses the use of paging technology for wireless transfer of traffic-related information from a central location to remote paging units. Users carrying pager receivers are continually updated on local traffic conditions extracted from a compiled traffic database. No provisions are made for collection of the data at the traffic sites for updating the database.
Some methods of data extraction from roadside monitoring devices involve a user stationed at a central computer to poll each device individually. When numerous devices are involved, as is the case in most state departments of transportation, such configurations prove to be cumbersome and time-consuming.
Further, the traditional methods of data collection from the roadside devices do not provide for convenient data sharing between several users. The conventional methods typically allow only one user at a central computer to poll the roadside monitoring devices and download, or otherwise receive, the traffic data. Special hardware and/or software, in addition to the central computer, are necessary for disseminating the collected traffic data to other users.
The present invention employs a wireless communication method that employs two-way paging technology in a manner that overcomes the drawbacks of the conventional wireless techniques.
The present invention responds to an immediate need for a reliable, cost-effective, and easy-to-implement wireless communication method in the context of telemetry with remote traffic monitoring devices. A convenient system and method are provided for collecting traffic data in a manner that allows multiple users to access the data over the Internet. The present invention relates to both of the primary data transfer aspects of traffic monitoring: from the traffic monitoring devices to a central computer, and from the central computer to the various users of the information collected.
The present invention utilizes the so-called xe2x80x9creverse channelxe2x80x9d of contemporary two-way paging technology, where a plurality of pager modems transmit traffic information from a plurality of remote devices to a central location.
Traffic information is extracted from roadside traffic monitoring devices using a micro-controller based communicating device. The extracted information is transmitted to a server via two-way paging technology, wherein multiple remote paging modems transmit data to a central location. Multiple users access the transmitted information stored at the server over the Internet. Advantages of the invention include:
Typically, traffic data such as volume, occupancy and speed represent small quantities of data in terms of bytes needed to store the data. Two-way paging is optimally suited for transmission of such small quantities of data.
With the wireless system of the present invention, installation cost is significantly less than the traditional telephone-based communication system. There is no need for the expensive trenching and installation of conduit as is necessary in a telephone-based system. Paging technology is also more reliable and cost-effective than other wireless communication methods, including cellular, radio and spread-spectrum.
With wireless technology, a monitoring device can be readily transported between locations. This is particularly useful in the field of event-based traffic management. Such systems are applicable to ongoing construction projects as well as major traffic events (ball games, conventions, etc.).
In a preferred embodiment, the system and method of the present invention results in a decentralized communication system, where each micro-controller based communicating device periodically queries the roadside monitoring device and automatically transmits periodic traffic information. There is no need for a user at a central computer to constantly poll the various field devices as in the contemporary configurations described above.
The present invention is intrinsically conducive for data-sharing among various agencies and information service providers. The transmitted data is reported to a central location, and is made accessible to a multitude of users over the Internet.
The present invention results in a more efficient data communication configuration Instead of a central computer having to make repeated calls to each field device, as in conventional architectures, under the proposed system, a user at a remote workstation queries the central location and downloads data from all the various field devices at once.
In a preferred embodiment of the system of the present invention, a micro-controller based communicating device periodically queries, and downloads data from, a roadside monitoring device. The communicating device transmits the data via a bi-directional paging network to a first xe2x80x9cmasterxe2x80x9d mailbox at an Internet computer server. The server copies the contents of the master mailbox to second xe2x80x9cuserxe2x80x9d mailboxes, each of which is assigned to an authorized user. The contents of the xe2x80x9cuserxe2x80x9d mailboxes are made available to the users to be accessed over the Internet using specialized software installed on their workstation.
The micro-controller based communicating device preferably comprises an integration of a pager modem and a single-board micro-controller (referred to henceforth as xe2x80x9cxcexcCxe2x80x9d). The pager modem preferably comprises a two-way narrow-band Personal Communication Services (PCS) transceiver supporting the ReFLEX(trademark) associate protocol. This communication method is widely used for two-way pagers to send and receive alpha-numeric messages. The communicating device is preferably able to interface with most roadside traffic monitoring devices through a serial port, for example an RS-232 serial port. This serial port or alternatively, a second serial port, further provides a pathway for uploading customized software onto flash memory located on the xcexcC, thereby allowing the communicating device to interface with virtually any traffic monitoring device. The communicating device is fbrther preferably provided with a timer/relay switch to deactivate the device during standby mode, enabling efficient battery power management.
The Internet server operates to receive the information transmitted by the various communicating devices, and stores the information in a first xe2x80x9cmasterxe2x80x9d mailbox. Subsequently, the information is copied into second xe2x80x9cuserxe2x80x9d mailboxes, each of which is assigned to a particular user. The user is provided access to his/her uniquely assigned mailbox through customized software resident on the user""s workstation. This software downloads the information contained within a user""s mailbox by connecting to the server over the Internet.
In one aspect, the present invention is directed to a method of communicating traffic-related data from a traffic monitoring device to a user. The method comprises collecting traffic-related data at a traffic monitoring device. The collected data is encoded according to wireless paging protocol. The encoded data is communicated via a wireless paging network, and received at a server. The received data is decoded according to the wireless paging protocol.
The collection of traffic-related data at the traffic monitoring device preferably comprises periodic polling the traffic monitoring device for updated traffic-related data. Encoding of the collected data preferably comprises periodically requesting data from the traffic monitoring device; receiving the requested data, encoding the data according to wireless paging protocol; and storing the encoded data The wireless paging network may be periodically polled to determine transmission availability; and when available, the encoded data is communicated over the wireless paging network.
The decoded data is preferably stored in a master mailbox and communicated from the master mailbox to a user mailbox. The received, decoded data may be accessed remotely, for example via the Internet.
In another aspect the present invention is directed to a system for communicating traffic-related data from a traffic monitoring device. The system comprises a traffic monitoring device for collecting traffic-related data. An encoder for encodes the collected data according to a wireless paging protocol. A pager modem communicates the encoded data over a wireless paging network A server receives the communicated encoded data, and decodes the received encoded data according to the wireless paging protocol.